Note to every dentist I’ve ever had:
“The reason we studied redheads in the beginning, it was essentially an urban legend in the anesthesia community saying redheads were difficult to anesthetize,” Dr. Sessler said. “This was so intriguing we went ahead and studied it. Redheads really do require more anesthesia, and by a clinically important amount.”
Yeah, like 20% more! And there’s an understanding that the same thing goes for pain medication. Beam me up, Scotty.
—from this New York Times article

I was totally unaware!